This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A047104 #4 Mar 30 2012 18:56:53 %S A047104 1,2,5,21,89,340,1312,5106,19782,76676,297776,1157609,4505193, %T A047104 17554888,68480902,267420957,1045329995,4089922224,16015961548, %U A047104 62768643959,246184737835,966243694608,3794894344275,14913585439328 %N A047104 T(n,n-2), array T as in A047100. %K A047104 nonn %O A047104 2,2 %A A047104 _Clark Kimberling_